1. Field of the Invention
The present invention relates generally to a measuring apparatus for surgical instrumentation and more particularly to an apparatus which effects measurement of a hernia defect to ascertain the corresponding necessary size of the repair material.
2. Background of the Invention
Hernias may be divided into three general classes--direct hernia, indirect hernia and femoral hernia. Direct or indirect hernias are usually characterized by a part of the intestine protruding through a defect n the supporting abdominal wall to form a hernia sac. This sac requires surgical repair which traditionally involved invasive repair and include a large incision. In order to reach the herniated portions, several layers of the abdominal wall must be separated. During the hernia repair procedure, to hernia is closed outside the abdominal wall in a manner which resembles the tying of a sack at the neck. A surgical mesh is usually then attached by sutures directly over the weakened abdominal wall opening to provide a reinforcement to the opening.
The above described traditional hernia repair amounts to a major invasive surgical procedure which frequently causes excessive trauma to the patient and results in an extended post-operative recuperative period. The need for cutting through the numerous tissue layers in order to access the herniated area also frequently causes severe trauma to the patient. Further, numerous complications related directly or indirectly to the surgery and including bleeding, infection, testicular atrophy, organ damage, nerve damage, blood vessel damage, etc., often enough result from repair performed by the traditional approach.
Today endoscopic surgery has replaced traditional hernia repair as the preferred procedure for correcting a wide variety of hernia defects. The benefits of endoscopic surgery for hernia repair include minimizing postoperative discomfort because no groin incision is made, minimizing the risk of injuries to the structures within the spermatic cord because the inguinal canal is not opened, and a reduction of migration because of the increased intraabdominal pressure holding the prosthetic mesh to the fascia. Endoscopic surgery also results in fewer of the above described complications.
In endoscopic procedures, surgery is performed in any hollow viscus of the body through narrow endoscopic tubes inserted through small entrance wounds in the skin; in laproscopic procedures, surgery is performed in the interior of the abdomen through a small incision. Laproscopic and endoscopic procedures generally require that any instrumentation inserted into the body be sealed, i.e., provisions must be made to ensure that gases do not enter or exit the body through the laproscopic or endoscopic incision as, for example, in surgical procedures in which the surgical region is insufflated. Moreover, laproscopic and endoscopic procedures often require the surgeon to act on organs, tissues and vessels far removed from the incision, thereby requiring that any instruments which are used in such procedures be long and narrow while being functionally controllable from one end of the instrument, i.e. the proximal end.
Endoscopic hernia repair is a minimally invasive procedure and is achieved by making several, usually three, small incisions in the abdomen through which a corresponding number of trocars are inserted. The various endoscopic instruments necessary to repair the hernia are inserted through the cannulas of these trocars. The endoscopic instruments inserted include a laparoscope for viewing the abdominal area, an apparatus for applying surgical staples to attach a prosthesis over the hernia opening, a prosthetic introducer and miscellaneous instruments such as graspers, dissectors and shears.
In an endoscopic procedure, the surgeon repairs the hernia by closing the hernia sac with a staple or clip and attaching a prosthesis over the opening similar to traditional hernia repair. In the endoscopic procedure, the proximal end of the various instruments which are located distally in the patient are manipulated and viewed by the surgeon through the laparoscope.
An essential part of the abdominal inguinal hernia repair procedure is the mesh prosthesis which closes either the internal inguinal or femoral ring and also reinforces the posterior wall of the inguinal canal. One example of a prosthetic material is polypropylene mesh sold under United States Surgical Corporation's trademark SURGIPRO. Alternatively, a piece of polytetrafluoroethylene (PTFE) can be rolled through a trocar and placed directly over the internal inguinal ring to cover the deep ring and posterior canal wall. Both of these prostheses are fixed in place by a surgical stapler.
The prosthesis to be applied should advantageously be tailored, i.e. sized, to correspond to the size of the defect to be repaired. Improper estimation of the size of the prosthesis requires withdrawal of the prosthesis through a trocar, resizing and repositioning in the preperitoneal location. Further, improper approximation can result in the waste of costly prosthetic material, a consideration not to be minimized in the current cost conscious health care environment. Also improper sizing requires that the patient remain under anesthia for a longer period of time, a negative even without the concern that hospitals bill based on the amount of time a patient actually spends in the operating room.
During a traditional hernia repair procedure, the surgeon could view the size of the defect and easily visually measure the size before preparing a correspondingly sized prosthetic. In endoscopic procedures, however, the herniated opening is far removed from the surgeon thereby preventing use of traditional and simple measurement techniques.
Presently during endoscopic hernia repair, the only way to approximate the size of the hernia defect is to view the image captured by the laparoscope and estimate the correct mesh size. Unfortunately, such estimates can be inaccurate and can result in the surgeon having to go through the aforementioned steps for withdrawal and resizing of the prosthesis.
Thus, there is a need to provide a device for accurately measuring the size of a hernia during an endoscopic repair procedure.
It would also be advantageous to provide a measuring device which is relatively inexpensive to manufacture.